The Laboratory core will provide sample preparation, storage, and laboratory assays for all four projects of the program project. A major goal of this core will be centralized sample processing, storage and retrieval, and most importantly, standardized assays of relevant specimens. As part of this goal, the core will expedite sample retrieval and data recording to encourage full utilization of the unique clinical specimens obtained during these studies. The core will provide both conventional serologic assays and solid phase RIA for measurement of antigen specific responses. A seroconversion EIA and confirmatory western blt has been modified for this study and will allow rapid and accurate determination of seroconversion in participants of the vaccine trial. As part of the effort to standardize assays and insure accurate analysis of samples from the various projects, the core will be responsible for assaying large numbers of serum specimens for virus neutralizing activity. Virus shredding will be detected by both conventional methods and rapid screening procedures, and virus excretion quantitated in patients identified in Projects 3. Finally, the core laboratory will also re responsible for the PCR detection of HCMV nucleic acids. The PCR assays will include a screening qualitative amplification followed by a quantitative competitive PCR. Quality control of the various assays performed in this core will be assured by close supervision of the laboratory direction and co-director. The laboratory core is well integrated into all of the projects described in this program because it serves as the central laboratory for each of the projects. Providing high quality laboratory support and sample storage is essential to successful completion of the overall goal of this program project.